The purpose of this study was to identify psychological, sociological and other factors associated immunization and other health outcomes. Mothers were enrolled in the study from three hospitals in the District of Columbia between August 1995 - September 1996. Mothers were interviewed shortly after giving birth. This "baseline" interview included information on sociodemographic characteristics of the mother, father and infant; the mothers medical history; psychosocial features of the family; and maternal knowledge, beliefs and practices surrounding well child care and immunizations and other health care practices. Two "follow-up" interviews were conducted, one when the infant was between three and seven months of age and one when the infant was between seven months and one year of age. A number of questions and topics covered on the baseline interview (e.g., perceived social norms regarding immunization practices) were repeated in the three and seven month interviews. Additionally, outcome data on health care practices, medical visits, and immunizations were collected during these "follow-up" interviews. Information obtained in the three and seven month interviews on immunizations and medical visits was verified via inspection of medical records at the identified provider sites. Manuscripts examining predictors of immunization and sleep position have been published. Recent analyses have focused on the prevalence of bed sharing. The purpose of this analysis was to determine the prevalence of infant-parent bed sharing; to examine stability in sleep practices during the first 7-12 months of life; and to identify factors associated with bed sharing. At both follow-up interviews almost half of infants usually slept with a parent or other adult. Sleep practices were relatively stable between the two interviews. A manuscript reporting these findings has been accepted for publication. Additional analyses are focusing on breastfeeding, and particularly on how contraindications to breastfeeding contribute to the low rates of breastfeeding among mothers enrolled in the study.